Many modern devices are capable of outputting high levels of electromagnetic energy in the form of radiation, such as high-energy lasers and high powered-lamps like solar simulator lamps. In certain circumstances, it is desirable to capture either a portion of or the entire output beam from such devices and, in either case, reduce the back-reflected and/or scattered radiation to zero. When a device is used to simply capture all or part of the radiant energy and no measurements of the beam are performed, such a device is generally referred to as a beam dump.
As a further example, it may be desirable to capture the output energy to measure the output level of the device. Such a measurement may be used to verify output levels of a device stated by a manufacturer or as a diagnostic tool for a radiation source. In this case, the beam capture assembly is generally referred to as a calorimeter or powermeter.
In either of the two cited examples, such a beam capture device must be capable of surviving the input radiation (which may be high power) and must capture substantially all of the radiation. In order to capture substantially all the radiation, the beam capture device should not permit excessive back-scatter, back-reflections or energy leakage, whereby radiation that has entered through an entrance of the beam capture device exits the beam capturing device though the entrance. Likewise, the device should not permit the radiation which has entered through an entrance of the device to escape through other passages.
Currently known beam capture devices may suffer from several shortcomings. For example, some currently known beam capture devices are bulky and heavy. Some current beam capture devices that suffer from this problem include plates that are tilted at large angles, long cones or linear wedges, and devices with torroidal axicon-type construction. Often an attempt is made to use a more compact design that results in local heating issues. The resultant geometry of such devices may, depending upon the level of input radiation, require cooling systems to dissipate the energy. Coolant systems are usually expensive to incorporate, and add to the complexity, bulk, and weight of these beam capture devices.
Further, some currently known beam capture devices are difficult and expensive to fabricate. For example, torroidal axicon devices, decreasing spiral radius devices, spherical devices, and conical devices include complex geometries that are complicated and time-consuming to fabricate.
Some currently known beam capture devices may be alignment sensitive; e.g. the attainment of good performance may require precise alignment. Examples include conical devices, linear wedges, and torroidal axicon devices.
Finally, currently known beam capture devices may exhibit excessive back-scatter or back-reflections. Types of beam capture devices that are subject to excessive back-scatter or back-reflections include tilted and un-tilted plates, cones, torroidal axicon devices, spiral radial devices, and linear wedges.
In an attempt to minimize back-scatter and back-reflections, currently known beam dumps may include a geometry requiring either a very sharp tip or a decreasing radius spiral, such as nautilus shell geometry. However, fabricating beam dumps with very sharp tips or decreasing radius spirals is extremely complicated and, therefore, very expensive.
As a result, there is an unmet need in the art for a beam capture device that is mechanically simple, compact, alignment insensitive, inexpensive to manufacture, requires no external cooling, and has minimal back-scatter and back-reflections.